Novel pillararene-based polymer material as well as preparation method and application thereof

Abstract

The invention is applicable to the technical field of organic photocatalysts, and provides a novel pillararene polymer material as well as a preparation method and application thereof. The metal-free organic catalyst polymer material TpAP [n] with semiconductor characteristics is designed and prepared by introducing supramolecular macrocyclic pillar aromatic hydrocarbon as a construction unit, the metal-free organic catalyst polymer material TpAP [n] is synthesized through a Schiff base condensation reaction, the unique interlayer ordered stacking limits the recombination of current carriers, an effective electron-hole transmission path is formed, and the metal-free organic catalyst polymer material TpAP [n] can be used for preparing a semiconductor material. More active sites are provided, and efficient contact between reactants and a catalytic center is facilitated. Experimental results show that the material can remarkably increase the generation rate of H2O2 under the illumination condition and shows excellent photocatalytic performance, the preparation process is environmentally friendly and conforms to the green chemistry principle, and a support and a theoretical basis are provided for design and preparation of subsequent series of metal-free organic catalysts.

Description

Technical Field

[0001] The invention belongs to the technical field of organic photocatalysts, and in particular relates to a novel pillar aromatic hydrocarbon-based polymer material and a preparation method and application thereof. Background Art

[0002] As an environmentally friendly and efficient oxidant, hydrogen peroxide (H2O2) has been widely used in organic synthesis, wastewater treatment, sterilization and disinfection, and pulp and papermaking. At present, the most commonly used method for preparing H2O2 is the anthraquinone method, which involves multiple steps. First, phenol reacts with excess acetone to form di(α-phenylmethyl)cyclohexanone. After that, di(α-phenylmethyl)cyclohexanone and anthraquinone undergo a series of complex oxidation reactions in the air to finally produce H2O2 and CO2. However, the preparation process of this method is complicated, including multiple reaction and separation steps, and the operation is cumbersome and time-consuming, resulting in inefficient and costly production processes. Secondly, the anthraquinone method often requires a large amount of energy input. These reactions usually need to be carried out under high temperature and high pressure conditions to promote reaction rate and yield, resulting in a large amount of energy consumption and exacerbating the problem of scarcity of energy resources. In addition, a large amount of wastewater is usually generated during the preparation of H2O2 by traditional methods. Wastewater contains unreacted raw materials, intermediates and catalyst residues, which need to go through a complex treatment and purification process to meet the discharge standards, which not only puts pressure on the environment, but also increases the economic burden. At the same time, the process is also accompanied by the generation of a large number of by-products, resulting in waste of resources and low energy efficiency. In order to overcome the above difficulties, the present invention proposes a new type of pillar aromatic hydrocarbon-based polymer material and its preparation method and application. Summary of the invention

[0003] The purpose of the present invention is to provide a new type of pillar aromatic hydrocarbon-based polymer material and a preparation method and application thereof, aiming to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions: A method for preparing a novel type of pillar aromatic hydrocarbon-based polymer material, wherein the synthesis route of the polymer material TpAP[n] is as follows: ; in: ; .

[0005] Further, when the polymer material donor has the following structural formula, the polymer material TpAP[5] is obtained; ; The preparation steps of the polymer material TpAP[5] are as follows: 26.2 mg of donor molecule aniline functionalized column [5] aromatic hydrocarbon and 4.2 mg of acceptor molecule trialdehyde pyrogallol were weighed and added to a 10 mL Shrek tube. Then, 2 mL of a mixed solution of 1,4-dioxane and mesitylene was added to the Shrek tube and ultrasonically treated until mixed evenly. 100 μL of 6 mol / L acetic acid solution was added and mixed evenly. The air in the Shrek tube was exchanged three times using a double-row tube to fill the bottle with nitrogen. The Shrek tube was placed in an oven at 120°C for reaction for 72 h to obtain a yellow powdery solid, which was washed with tetrahydrofuran and dried to obtain the polymer material TpAP [5].

[0006] A type of novel pillar aromatic hydrocarbon-based polymer material prepared according to the preparation method of the novel pillar aromatic hydrocarbon-based polymer material described above.

[0007] A class of applications of the novel pillar aromatic hydrocarbon-based polymer materials described above in photocatalytic H2O2 production.

[0008] Compared with the prior art, the present invention has the following beneficial effects: The present invention introduces supramolecular macrocyclic pillar aromatic hydrocarbons as building blocks to design and prepare a metal-free organic catalyst polymer material TpAP[5] with semiconductor properties. It is synthesized through Schiff base condensation reaction. Its unique interlayer ordered stacking limits the recombination of carriers, forms an effective electron-hole transport path, and provides more active sites, which is conducive to the efficient contact between reactants and catalytic centers. Experimental results show that the material can significantly increase the generation rate of H2O2 under light conditions, showing excellent photocatalytic performance. The preparation process is environmentally friendly and in line with the principles of green chemistry, providing support and theoretical basis for the design and preparation of subsequent series of metal-free organic catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 The physical and chemical properties of TpAP[5] are characterized by (a) the thermogravimetric curve of TpAP[5]; (b) the scanning electron microscope image of TpAP[5]; (c) the X-ray photoelectron spectrum of TpAP[5]; and (d) the infrared spectrum of TpAP[5].

[0010] Figure 2 A standard curve of H2O2 was generated for TpAP[5].

[0011] Figure 3 This is the UV absorption spectrum of H2O2 produced by TpAP[5] detected by iodine titration.

[0012] Figure 4The performance and property characterization diagrams of TpAP[5]; among them, (a) is the electrochemical impedance spectrum of TpAP[5]; (b) is the photocurrent spectrum of TpAP[5]; (c) is the photocatalytic H2O2 production rate diagram of TpAP[5] and TpDT; (d) is the electron paramagnetic resonance spectrum of TpAP[5]. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0014] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0015] Example 1: Preparation of polymer material TpAP[5] with aniline-modified pillar[5]arene as building block; Weigh 26.2 mg of aniline functionalized column [5] aromatic hydrocarbon (APP[5]) and 4.2 mg of trialdehyde phloroglucinol (Tp) into a 10 mL Shrek tube. The two reactants will polymerize through Schiff base condensation reaction. Add 2 mL of a mixed solution of 1,4-dioxane and mesitylene to the Shrek tube, treat with ultrasound until mixed, add 100 μL of 6 mol / L acetic acid solution, and mix well. Use a double-row tube to exchange the air in the Shrek tube three times to fill the bottle with nitrogen. Place the Shrek tube in a 120℃ oven for reaction for 72 h to obtain a yellow powder solid, which is washed with tetrahydrofuran several times and dried to obtain the polymer material TpAP[5].

[0016] The synthesis route of the polymer material TpAP[5] is as follows: ; in: ; .

[0017] like Figure 1 As shown in (a)-(d), different characterization methods are used to demonstrate the successful preparation and properties of the polymer material TpAP[5]. Figure 1 As can be seen in (a), TpAP[5] begins to show a significant mass decline at 390°C, but still retains 62% of its mass at 900°C, indicating that the material has good thermal stability. Figure 1(b) shows the microscopic morphology of TpAP[5] observed by scanning electron microscopy, which shows that it is basically spherical. It is worth noting that the orderly stacking of TpAP[5] not only limits the recombination of carriers, but also forms an effective electron-hole transport path and provides more active sites, which is conducive to the efficient contact between reactants and catalytic centers. In addition, the carbon, nitrogen and oxygen elements that constitute the main body of the material are also shown in the X-ray photoelectron energy spectrum, see Figure 1 (c). Figure 1 As shown in (d), the infrared spectrum compares the characteristic peaks of the polymer material TpAP[5] and the monomer. With the disappearance of the amine peak and the formation of carbon-carbon double bonds, it can be determined that the polymerization of TpAP[5] is successful.

[0018] Example 2: Construction of a photocatalytic H2O2 production catalytic system based on TpAP[5]; The catalyst and deionized water are mixed in a certain ratio (1:5-1:10) to prepare a suspension (sacrificial agents can also be added to the solution, including but not limited to organic substances such as ethanol, to promote electron transfer, thereby improving the efficiency of H2O2 production). Oxygen is passed through the reaction system for 40-60 minutes to place the suspension in an oxygen-rich environment, and stirred in a closed, light-free environment until adsorption equilibrium is reached. A visible light source is introduced, and the system temperature is controlled to remain at room temperature. A fixed amount (1-3 mL) of the reaction solution is extracted every 10 minutes, and the catalyst material is removed by centrifugation. 1 mL of 0.1 mol / L C8H5O4K solution and 1 mL of 0.4 mol / L potassium iodide (KI) solution are added in sequence and mixed thoroughly. Since H2O2 can absorb I in KI solution, - Oxidized to free iodine, the free iodine will react with the remaining I - Generate I3 - , detected at a specific wavelength (e.g. 352 nm). After 30 min of reaction, I3 - The corresponding absorption value of Figure 2 As shown in the figure, the relationship between absorbance and concentration calculated by Lambert-Beer law can be used to establish a standard curve, such as Figure 3 As shown in the figure, the absorbance value of the reaction solution at 352 nm is measured, and the obtained annotation curve is inserted into the corresponding concentration conversion to monitor I3 in real time. - The concentration of H2O2 and its production rate can be calculated by analyzing the changes in concentration.

[0019] Example 3: Control experiment on the effect of whether the catalyst has a pillar aromatic structure on the catalytic rate; The results are as follows Figure 4As shown in (a) and (b), TpAP[5] exhibits smaller impedance and better photocurrent responsiveness than the control material (formed by polymerization of 4,4''-diaminoterphenyl and pyrogallol trialdehyde, TpDT), indicating that TpAP[5] has a relatively higher photocatalytic potential. The TpAP[5] material with a pillar aromatic structure and the control material were tested under the same reaction conditions. The results are shown in Figure 2. Figure 4 As shown in (c), TpAP[5] exhibits a significant rate advantage (2343 μmol g⁻¹ h⁻¹), which is twice that of the control material (1083 μmol g⁻¹ h⁻¹), and the catalytic efficiency remains basically unchanged after multiple (3) cycles. Figure 4 As shown in (d), the electron paramagnetic resonance spectrum of TpAP[5] shows four characteristic peaks, indicating that the superoxide radical, a characteristic active oxygen species in the photocatalytic process, has been detected. This facilitates the investigation of the factors affecting the rate-determining step in order to optimize the performance of subsequent series of materials.

[0020] The above are only preferred embodiments of the present invention. It should be pointed out that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention. These should also be regarded as the protection scope of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A method for preparing a novel type of pillar aromatic hydrocarbon-based polymer material, characterized in that: The synthetic route of the polymer material TpAP[n] is as follows: ； in: ； 。 2. The method for preparing the novel pillar aromatic hydrocarbon-based polymer material according to claim 1, characterized in that: When the structural formula of the polymer material donor is as follows, the polymer material TpAP[5] is obtained; ； The preparation steps of the polymer material TpAP[5] are as follows: 26.2 mg of donor molecule aniline functionalized column [5] aromatic hydrocarbon and 4.2 mg of acceptor molecule trialdehyde pyrogallol were weighed and added to a 10 mL Shrek tube. Then, 2 mL of a mixed solution of 1,4-dioxane and mesitylene was added to the Shrek tube and ultrasonically treated until mixed evenly. 100 μL of 6 mol / L acetic acid solution was added and mixed evenly. The air in the Shrek tube was exchanged three times using a double-row tube to fill the bottle with nitrogen. The Shrek tube was placed in an oven at 120°C for reaction for 72 h to obtain a yellow powdery solid, which was washed with tetrahydrofuran and dried to obtain the polymer material TpAP [5].

3. A new type of pillar aromatic hydrocarbon-based polymer material obtained according to the preparation method of the new type of pillar aromatic hydrocarbon-based polymer material according to claim 1.

4. An application of the novel pillar aromatic hydrocarbon-based polymer material according to claim 3 in photocatalytic production of H2O2.

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